2,557 research outputs found
LEAF CARBON-ISOTOPE DISCRIMINATION AND VEGETATIVE RESPONSES OF DRYAS-OCTOPETALA TO TEMPERATURE AND WATER MANIPULATIONS IN A HIGH ARCTIC POLAR SEMIDESERT, SVALBARD
Brain activation during face perception: evidence of a developmental change.
Behavioral studies suggest that children under age 10 process faces using a piecemeal strategy based on individual distinctive facial features, whereas older children use a configural strategy based on the spatial relations among the face's features. The purpose of this study was to determine whether activation of the fusiform gyrus, which is involved in face processing in adults, is greater during face processing in older children (12-14 years) than in younger children (8-10 years). Functional MRI scans were obtained while children viewed faces and houses. A developmental change was observed: Older children, but not younger children, showed significantly more activation in bilateral fusiform gyri for faces than for houses. Activation in the fusiform gyrus correlated significantly with age and with a behavioral measure of configural face processing. Regions believed to be involved in processing basic facial features were activated in both younger and older children. Some evidence was also observed for greater activation for houses versus faces for the older children than for the younger children, suggesting that processing of these two stimulus types becomes more differentiated as children age. The current results provide biological insight into changes in visual processing of faces that occur with normal development
DNA polymerase δ-dependent repair of DNA single strand breaks containing 3′-end proximal lesions
Base excision repair (BER) is the major pathway for the repair of simple, non-bulky lesions in DNA that is initiated by a damage-specific DNA glycosylase. Several human DNA glycosylases exist that efficiently excise numerous types of lesions, although the close proximity of a single strand break (SSB) to a DNA adduct can have a profound effect on both BER and SSB repair. We recently reported that DNA lesions located as a second nucleotide 5′-upstream to a DNA SSB are resistant to DNA glycosylase activity and this study further examines the processing of these ‘complex’ lesions. We first demonstrated that the damaged base should be excised before SSB repair can occur, since it impaired processing of the SSB by the BER enzymes, DNA ligase IIIα and DNA polymerase β. Using human whole cell extracts, we next isolated the major activity against DNA lesions located as a second nucleotide 5′-upstream to a DNA SSB and identified it as DNA polymerase δ (Pol δ). Using recombinant protein we confirmed that the 3′-5′-exonuclease activity of Pol δ can efficiently remove these DNA lesions. Furthermore, we demonstrated that mouse embryonic fibroblasts, deficient in the exonuclease activity of Pol δ are partially deficient in the repair of these ‘complex’ lesions, demonstrating the importance of Pol δ during the repair of DNA lesions in close proximity to a DNA SSB, typical of those induced by ionizing radiation
Fire Alters Plant Microbiome Assembly Patterns: Integrating the Plant and Soil Microbial Response to Disturbance
It is increasingly evident that the plant microbiome is a strong determinant of plant health. While the ability to manipulate the microbiome in plants and ecosystems recovering from disturbance may be useful, our understanding of the plant microbiome in regenerating plant communities is currently limited. Using 16S ribosomal RNA (rRNA) gene and internal transcribed spacer (ITS) region amplicon sequencing, we characterized the leaf, stem, fine root, rhizome, and rhizosphere microbiome of \u3c 1-yr-old aspen saplings and the associated bulk soil after a recent high-intensity prescribed fire across a burn severity gradient. Consistent with previous studies, we found that soil microbiomes are responsive to fire. We extend these findings by showing that certain plant tissue microbiomes also change in response to fire. Differences in soil microbiome compositions could be attributed to soil chemical characteristics, but, generally, plant tissue microbiomes were not related to plant tissue elemental concentrations. Using source tracking modeling, we also show that fire influences the relative dominance of microbial inoculum and the vertical inheritance of the sapling microbiome from the parent tree. Overall, our results demonstrate how fire impacts plant microbiome assembly, diversity, and composition and highlights potential for further research towards increasing plant fitness and ecosystem recovery after fire events
The Effect of Galaxy Interactions on Molecular Gas Properties
© 2018. The American Astronomical Society. All rights reserved.Galaxy interactions are often accompanied by an enhanced star formation rate (SFR). Since molecular gas is essential for star formation, it is vital to establish whether and by how much galaxy interactions affect the molecular gas properties. We investigate the effect of interactions on global molecular gas properties by studying a sample of 58 galaxies in pairs and 154 control galaxies. Molecular gas properties are determined from observations with the JCMT, PMO, and CSO telescopes and supplemented with data from the xCOLD GASS and JINGLE surveys at 12CO(1-0) and 12CO(2-1). The SFR, gas mass (), and gas fraction (f gas) are all enhanced in galaxies in pairs by ∼2.5 times compared to the controls matched in redshift, mass, and effective radius, while the enhancement of star formation efficiency (SFE ≡SFR/) is less than a factor of 2. We also find that the enhancements in SFR, and f gas, increase with decreasing pair separation and are larger in systems with smaller stellar mass ratio. Conversely, the SFE is only enhanced in close pairs (separation <20 kpc) and equal-mass systems; therefore, most galaxies in pairs lie in the same parameter space on the SFR- plane as controls. This is the first time that the dependence of molecular gas properties on merger configurations is probed statistically with a relatively large sample and a carefully selected control sample for individual galaxies. We conclude that galaxy interactions do modify the molecular gas properties, although the strength of the effect is dependent on merger configuration.Peer reviewedFinal Accepted Versio
Effects of lower limb amputation on the mental rotation of feet
What happens to the mental representation of our body when the actual anatomy of our body changes? We asked 18 able-bodied controls, 18 patients with a lower limb amputation and a patient with rotationplasty to perform a laterality judgment task. They were shown illustrations of feet in different orientations which they had to classify as left or right limb. This laterality recognition task, originally introduced by Parsons in Cognit Psychol 19:178–241, (1987), is known to elicit implicit mental rotation of the subject’s own body part. However, it can also be solved by mental transformation of the visual stimuli. Despite the anatomical changes in the body periphery of the amputees and of the rotationplasty patient, no differences in their ability to identify illustrations of their affected versus contralateral limb were found, while the group of able-bodied controls showed clear laterality effects. These findings are discussed in the context of various strategies for mental rotation versus the maintenance of an intact prototypical body structural description
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An exploration of the experiences and self-generated strategies used when navigating everyday life with Long Covid.
BACKGROUND: Around one in ten people who contract Covid-19 report ongoing symptoms or 'Long Covid'. Without any known interventions to cure the condition, forms of self-management are routinely prescribed by healthcare professionals and described by people with the condition. However, there is limited research exploring what strategies are used to navigate everyday life with Long Covid, and experiences that initiate development of these strategies. Our study aimed to explore the range and influence of self-generated strategies used by people with Long Covid to navigate everyday life within the context of their own condition. METHODS: Forming part of the Long Covid Personalised Self-managemenT support co-design and EvaluatioN (LISTEN) project, we conducted a qualitative study using narrative interviews with adults who were not hospitalised with Covid-19. Participants aged over 18 years, who self-identified with Long Covid, were recruited from England and Wales. Data were analysed with patient contributors using a reflexive thematic analysis. RESULTS: Eighteen participants (mean age = 44 years, SD = 13 years) took part in interviews held between December 2021 and February 2022. Themes were constructed which depicted 1) the landscape behind the Long Covid experience and 2) the everyday experience of participants' Long Covid. The everyday experience comprised a combination of physical, emotional, and social factors, forming three sub-themes: centrality of physical symptoms, navigating 'experts' and the 'true colour' of personal communities, and a rollercoaster of psychological ambiguity). The third theme, personal strategies to manage everyday life was constructed from participants' unique presentations and self-generated solutions to manage everyday life. This comprised five sub-themes: seeking reassurance and knowledge, developing greater self-awareness through monitoring, trial and error of 'safe' ideas, building in pleasure and comfort, and prioritising 'me'. CONCLUSIONS: Among this sample of adults with Long Covid, their experiences highlighted the unpredictable nature of the condition but also the use of creative and wide ranging self-generated strategies. The results offer people with Long Covid, and healthcare professionals supporting them, an overview of the collective evidence relating to individuals' self-management which can enable ways to live 'better' and regain some sense of identity whilst facing the impact of a debilitating, episodic condition. TRIAL REGISTRATION: LISTEN ISRCTN36407216
Identification of rare microbial colonizers of plastic materials incubated in a coral reef environment
Plastic waste accumulation in marine environments has complex, unintended impacts on ecology that cross levels of community organization. To measure succession in polyolefin-colonizing marine bacterial communities, an in situ time-series experiment was conducted in the oligotrophic coastal waters of the Bermuda Platform. Our goals were to identify polyolefin colonizing taxa and isolate bacterial cultures for future studies of the biochemistry of microbe-plastic interactions. HDPE, LDPE, PP, and glass coupons were incubated in surface seawater for 11 weeks and sampled at two-week intervals. 16S rDNA sequencing and ATR-FTIR/HIM were used to assess biofilm community structure and chemical changes in polymer surfaces. The dominant colonizing taxa were previously reported cosmopolitan colonizers of surfaces in marine environments, which were highly similar among the different plastic types. However, significant differences in rare community composition were observed between plastic types, potentially indicating specific interactions based on surface chemistry. Unexpectedly, a major transition in community composition occurred in all material treatments between days 42 and 56 (p < 0.01). Before the transition, Alteromonadaceae, Marinomonadaceae, Saccharospirillaceae, Vibrionaceae, Thalassospiraceae, and Flavobacteriaceae were the dominant colonizers. Following the transition, the relative abundance of these taxa declined, while Hyphomonadaceae, Rhodobacteraceae and Saprospiraceae increased. Over the course of the incubation, 8,641 colonizing taxa were observed, of which 25 were significantly enriched on specific polyolefins. Seven enriched taxa from families known to include hydrocarbon degraders (Hyphomonadaceae, Parvularculaceae and Rhodobacteraceae) and one n-alkane degrader (Ketobacter sp.). The ASVs that exhibited associations with specific polyolefins are targets of ongoing investigations aimed at retrieving plastic-degrading microbes in culture
Improving PARSEC models for very low mass stars
Many stellar models present difficulties in reproducing basic observational relations of very low mass stars (VLMS), including the mass-radius relation and the optical colour-magnitudes of cool dwarfs. Here, we improve PARSEC (PAdova-TRieste Stellar Evolution Code) models on these points. We implement the T- \ufffd relations from PHOENIX BT-Settl model atmospheres as the outer boundary conditions in the PARSEC code, finding that this change alone reduces the discrepancy in the mass-radius relation from 8 to 5 per cent. We compare the models with multiband photometry of clusters Praesepe and M67, showing that the use of T- \ufffd relations clearly improves the description of the optical colours and magnitudes. But anyway, using both Kurucz and PHOENIX model spectra, model colours are still systematically fainter and bluer than the observations. We then apply a shift to the above T- \ufffd relations, increasing from 0 at Teff = 4730 K to ~14 per cent at Teff = 3160 K, to reproduce the observed mass-radius relation of dwarf stars. Taking this experiment as a calibration of the T- \ufffd relations, we can reproduce the optical and near-infrared colour-magnitude diagrams of low-mass stars in the old metal-poor globular clusters NGC 6397 and 47 Tuc, and in the intermediate-age and young solar-metallicity open clusters M67 and Praesepe. Thus, we extend PARSEC models using this calibration, providing VLMS models more suitable for the lower main-sequence stars over a wide range of metallicities and wavelengths. Both sets of models are available on PARSEC webpage. \ufffd 2014 The Authors
Listening in Pheromone Plumes: Disruption of Olfactory-Guided Mate Attraction in a Moth by a Bat-Like Ultrasound
Nocturnal moths often use sex pheromones to find mates and ultrasonic hearing to evade echolocating bat predators. Male moths, when confronted with both pheromones and sound, thus have to trade off reproduction and predator avoidance depending on the relative strengths of the perceived conflicting stimuli. The ultrasonic hearing of Plodia interpunctella was investigated. A threshold curve for evasive reaction to ultrasound of tethered moths was established, and the frequency of best hearing was found to be between 40 and 70 kHz. Flight tunnel experiments were performed where males orienting in a sex pheromone plume were stimulated with 50 kHz pulses of different intensities. Pheromone-stimulated males showed increased defensive response with increased intensity of the sound stimulus, and the acoustic cue had long-lasting effects on their pheromone-mediated flight, revealing a cost associated with vital evasive behaviours
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